Centric relator



Dec. l2, 1950 s. H. HlRscHHoRN CENTRIC RELATOR 3 Sheets-Sheet 1 Filed Sept. 25, 1949 IN VEN TOR. w/vfy b. #wsa/HORN Dec. l2, 1950 s. H. HlRscHHoRN CENTRIC RELATOR 3 Sheets-Sheet 2 Filed Sept. 23, 1949 INVENTOR.

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CENTRIC RELAToR Filed Sept. 25, 1949 3 Sheets-Sheet 3 Arme/mf Patented Dec. 12, 1950 UNITED STATS l) TENT GFFICE CENTRIC RELATOR Sidney H. Hirschhorn, Paterson, N. J.

Application September 23, 1949, Serial No. 117,322

9 Claims.

This application is a continuation in part of my application Serial No. 47,460, iiled September 2, i948, now abandoned.

This invention relates to a straight line articulator used in the art of dentistry. It particularly concerns the making of full dentures, partial dentures, and the construction and use of study models.

In making dentures a rather complex series of operations is followed. In general, an impression is taken of thernouth, plaster casts of the upper and lower jaws being made. These plaster casts are mounted on a machine, but they are 'not properly related, and before perfect dentures can be made, they rnust have the same centric relationship as the patients jaws. In order to obtain that relationship a wax bite block is bitten into by the patient, and furnishes this necessary relationship. The bite blocks are mounted on the plaster models and can be removed from it. The

plaster models are usually mounted in a machine called an articulator that has supports for t. e plaster models bearing the bite blocks. The dentures are set up in the wax of bite block and the blocks are moved back and forth -irorn casts to the patients mouth in order to accomplish perfect tting. However, former machines many had no way to correct error except to dismount the plaster of one model and remount it on a new plaster record of the mouth. Some y machines had kind of adjustment by screws or planes that was a problem in. itself, necessitating independent, unconnected, unrelated, and unbalanced movements.

The setting of the two models requires a .forward and backward movement to right and left, and an up and down motion that becomes a mathematical problem of delicate proportions which dicult, laborious, time-consuming, inaccurate, and frequently nerve-racking. The instrument itself becomes a problem and the adjustment is sometimes almost impossible.

it is an object of this invention to correct error in the relationship of forms produced from the wax hte block or from any other 'transitional material available.

Another object is to correct the error when centric arrangement of the teeth fails to coincide.

Another object is to accomplish the proper arrangement with the assistance of the patient at the chair, the patient and the instrument being used simultaneously and interchangeably.

Another object of the invention is to have an instrument for establishing centric relationship that is adjustable to a centric relationship brought to it.

A further object is to seat the two jaws into a guide called the centric relationship record.

In order to accomplish the objects of the in.- vention, I have produced a centric relatorA which has no resistance to movement in any direction, forward. backward, right, left, up, down, and spherical.

In the accompanying drawings, wherein like reference characters refer to like parts throughout the several views.

Fig. l is a vertical side view of the centric relator;

Fig. 2 .is a vertical front view thereof;

Fig. 3 is a detail of the articulated arm;

Fig. 4 is a detail of the universal joint;

Fig. 5 is an elevational view, partly in section, ci a modified form of the device; and

Fig. 6 is a section on line S-E of Fig. 5.

In the drawings, numeral I@ indicates a pedestal to which is attached by screws H a socket lll having a screw threaded extension i3. The socket l2 has a cylinder hole lll upon the bottom of which are two movable blocks l5, l5, the upper surfaces of which have cooperating parts l i, i8 of a spherical seat. A screw threaded shaft 20 penetrates the socket l2, passes through block l5, and is screw threaded into the block I6, an arrangement which permits the blocks to be moved toward and away from each other and to grip and release the ball. A ball 2l carrying on one side a supporting stud 22 is received in the seats ll, lli of blocks l5, l5 and is held therein by a cap 23 which is screw threaded upon extension i3 and has an internal spherical seat 2li. Thus, the support 22 is mounted for spherical movement but can be locked in position by use of the thumb screw 2li which jams the .ball 2l against the seat 2i by drawing the blocks iii, l5 together.

A metallic supporting plate 25, which carries the form 2t, may be mounted upon the stud 22 as indicated in dotted lines in Fig. l and may be spherically moved to any desired position.

Also mounted upon the pedestal lli is an articulated column 3S, 3l, the upper part 3l oi' which is mounted upon the lower part 3B by a horizontal pivot pin 32. The upper portion of column part 3S is forked as shown at 33, 34 and receives between the parts of the fork a snugly fitting ilange 35 on the lower end of part 3l. The u per surfaces 35 of the fork are flat and angu- 'arly arranged, and the lower portions 3l of the part 3l, just above the iiange are similarly iiattened and angled. Consequently, in the position shown in I, the column Sie is fixed :in upright position. It can be pivoted vertically backward, but not forward. The pin is controlled by a thumb screw 32 which locks parts Ei in any desired angular relationship.

The top of the column St, 3l is flattened near its circumference as shown at 39 in Fig. S and has a projecting cylindrical stud iii which receives a snugly -fitting sleeve ii on an articulated arm i2-d3. The sleeve il is somewhat longer than the stud #le so that a screw threaded pin on the end of thumb screw 44, seated in the stud 4D, serves to fix the arm 42 in any selected angular position. The parts of the arm 42, 43 are articulated by means of a bolt 58 which passes through sleeves 52 in the forked end of arm part 43 and through a sleeve 53 in the end of arm part 42. In this case also the bolt 50 is slightly shorter than the distance of the opposite faces of the fork 5|, 52 so that a thumb screw 54 can be employed by means of internal screw thread 55 to x the parts 42, 43 in selected elbow relationship.

The outer end of arm 42, 43 contains a sleeve 60 having a slot 6l. In this sleeve there is received a shaft 62 having a spline 63 which is received in slot 6|. A thumb screw 64 penetrates the end of the arm 43 and serves to seat the shaft 62 in selected vertical position. The support 62 carries at its lower end a ball and socket joint similar in construction to that which has heretofore been described and is shown in Fig. 4. On a stud 1i of said ball and socket joint'there may be mounted a metal plate 12. A small rod 62 adjustably set in the sleeve 62 by a set screw establishes a precise position of the shaft 62 in the sleeve at the end of arm 43, even when screw 64 is loose.

In Fig. 5 .is shown a modified form of the invention. In this gure 1l indicates a lower denture support which is carried in ixed relation to the base 12 of the apparatus. This support 'H may also be universally mounted as indicated in Figs. l to 4. One object of this modification is to indicate variations in structure which can sometimes be usefully employed. A standard 12 is carried by the support and is vertically articulated at 13, the upper portion of the standard 12" being pivoted to lowel` portion 12 for vertical motion. The vertical motion referred to herein should generally be considered as vertical with respect to the plane of support 1|. The upper end of the shaft 12 is reduced at 14 and serves as a support for arm 12 of the standard 12. The standard 12 is thus provided with a vertical articulation which permits the support 1| to be moved away from support 1I. the side of arm 12 and a locking piece 16 is mounted on the lower portion 12 of the standard and can be swung into locking engagement with the pin so as to keep the arm 12" xed in its horizontal position when desired. The end of the arm 12 is provided with a universal joint 11 which includes a sphere 19 within the socket which is capable of being locked in position by jam lugs 88, 8l operated by a thumb screw 82.

The shaft 83 passes through the ball 19 and is given limited universal motion within the casing 18 by releasing the thumb screw 82. In this way, the position of the shaft 83 at its lower end can be varied sufliciently to accommodate all normal variations required by the instrument. At the lower end of shaft 83 is a universal joint 84 of the type which has been described hereinbefore which is in turn, connected to the denture support 1l'. The shaft 83 is adjustably held in the ball by a screw 85 which can be released and tightened at will, an aperture in the side of the casing 18 allowing this screw the same liberty of motion which is permitted the shaft 83.

By virtue of the construction which has just been described, there is no resistance to movement in any direction, but all movements are connected and interconnected, related and interrelated. There is relative movement in unity. All movements can be made simultaneously and can balance opposing movements. The entire instru- A pin projects from ment is based on a series of related balances at work for each other. The number of individual movements required by prior art structures is greatly reduced by combination. Once the mechanism is locked the forms can be separated and brought back together again in perfect alignment by simple motion of the part 3l about elbow 32. The movements are based on circles rather than on planes and screw adjustments thereof.

In locking the flat plane type of relator the probability is that there will be a change at the centric relationship end that will produce an incorrect relationship. There is almost always error introduced when flat planes are locked. With screws error still exists because you cannot tell whether you are correctly seated in the record. In operating the device, the two senses involved are sight and touch, and in the last analysis, touch is the more important because it is the final test of accuracy. This is operative in the present apparatus but not in those of the prior art of the plane and screw type.

If correction is necessary, time and steps are saved in dismounting and remounting forms.

This device gives a direct vertical opening.

It is possible to mount the jaw members independently and away from each other, bringing them into proper relation almost instantly, when wanted.

Another advantage is that complete rotation of the dentures on their axis without changing relationship is possible. This makes for clear and unimpeded view and working conditions.

It is possible to test the inclination of the teeth by tactile sense. This is very important when it is considered that the tactile sense is the only means that the patient has for observing the nature of the arrangement of teeth in his mouth.

Each jaw can be set up independently and prior to gathering the relationship, and this is believed to be the only instrument which permits it, and that can be used at the chair in making corrections in jaw relationship that are brought to the instrument. It does not require any of the jaw members to be removed if the centric relationship is incorrect.

As many apparently widely diierent embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments.

What is claimed is:

1. A centric relator including a pedestal, a form support universally mounted on the pedestal, an elbowed column mounted on the pedestal having a vertically tiltable top, a horizontally elbowed arm horizontally pivoted upon the column, a rod vertically and adjustably supported by the arm, a form support universally carried by the said rod, and means to x each joint of said relator in selected position.

2. A centric relator having opposed form supports, spherically jointed supporting means for one said support, and spherically jointed, vertically adjustable, horizontally and vertically articulated supporting means for said opposed support, and means to fix each said articulation and spherical joint in selected position.

3. A centric relator for dentures including cooperative, universally mounted supports, and supporting means for one said support including a vertical articulation, two horizontal articulations, and a vertical adjustment.

4. A centric relator for dentures including cooperative, opposed supports for dentures, and supporting means for one said support including a vertical articulation, two horizontal articula.- tions, a vertical adjustment, and a universal joint.

5, A centr-ic relator for dentures comprising opposed denture supports, afstandard having a vertical articulation, a universalijont carried by the standard in alignment witlqrsaid supports, a shaft adjustably mounted in 'tlie universal joint for axial motion, and a univer l'joint connecting said shaft and one of said defn (e supports.

6. A centric relator for dentures comprising opposed supports for dentures; and supporting means for one said support including a vertical articulation, a pair of universal joints, and a vertical adjustment.

7. A centric relator for dentures comprising opposed supports for dentures, and supporting means for one of said supports comprising a universal joint, a shaft attached thereto and mounted for vertical adjustment in a second universal joint, an arm supporting said second universal joint, and a vertically adjustable joint supporting said arm.

8. A centric relator having opposed denture supports, one of said supportsv being positioned REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 537,812 Bragg Apr. 23, 1895 1,654,453 Brown Dec. 27, 1927 1,736,006 Hagman Nov. 19, 1929 2,095,665 Greth Oct. 12, 1937 2,275,726 Burns et al Mar. 10, 1942 FOREIGN PATENTS Number Country Date 328.866 Italy Aug. 22, 1935 

